The purpose of this project is to study the process of relapse following cessation of cigarette smoking, and to develop and test methods of intervention designed to prevent such relapse. Data on the relapse process is being collected from ex-smoker subjects who call a telephone hot-line serving ex-smokers who are at risk for relapse. Each caller who has experienced a relapse is debriefed concerning the details of the relapse episode. A description of the physical and social environment in which the relapse occurred is also obtained. In a second aspect of the project, smoking cessation clinics are conducted using programs designed to enhance the ex-smoker's skills in maintaining abstinence. Data from the hot-line concerning the likelihood of relapse in particular situations is used to develop interventions targeted to these high-risk situations. A follow-up program is under way to determine the success of these strategies as well as to study individual differences in situational susceptibility to relapse.